The proposed research project involves the detailed investigation of structure, binding properties and transport function of bovine serum high-density lipoprotein (BHDL). In the work on BHDL structure, the experiments I propose to carry out on apolipoprotein behavior in solution and the systematic investigation of the perturbation of BHDL structure by chemical and physical means, using fluorescence techniques, are new approaches to the problem of high density serum lipoprotein structure, and are expected to contribute significantly to this are of research. A general understanding of lipoprotein structure and protein-lipid interactions in these relatively simple systems would be extremely important for the understanding of biological membranes. Another research goal in may proposal is the elucidation of the transport function of BHDL beyond the lipid-carrier role tha has traditionally been attributed to serum lipoproteins. The quantitative studies which I propose to carry out on BHDL binding of non-polar molecules, hydrophobic anions, hydrophilic molecules, drugs, and hormones, using ultracentrifugal and spectroscopic techniques, are completely new investigations of lipoprotein properties. This work, together with experiments of BHDL binding-competition with other serum proteins and interaction with cellular membranes, should contribute to the understanding of the entire transport system in mammalian serum, and to the investigation of cardiovascular diseases.